1 /* SPDX-License-Identifier: GPL-2.0-only */
2
3 #include <commonlib/bsd/ipchksum.h>
4 #include <console/console.h>
5 #include <pc80/mc146818rtc.h>
6
7 #include "cse_lite_cmos.h"
8
9 /*
10 * We need a region in CMOS to store the firmware versions.
11 *
12 * This can either be declared as part of the option
13 * table or statically defined in the board config.
14 */
15 #if CONFIG(USE_OPTION_TABLE)
16 # include "option_table.h"
17
18 #ifndef CMOS_VSTART_partition_fw
19 #error "The `CSE partition firmware` CMOS entry is missing, please add it to your cmos.layout."
20 #endif
21
22 #if CMOS_VSTART_partition_fw % 8 != 0
23 #error "The `CSE partition firmware` CMOS entry needs to be byte aligned, check your cmos.layout."
24 #endif // CMOS_VSTART_partition_fw % 8 != 0
25
26 #if CMOS_VLEN_partition_fw != (32 * 8)
27 #error "The partition firmware entry needs to be 32 bytes long, check your cmos.layout."
28 #endif
29
30 # define PARTITION_FW_CMOS_OFFSET (CMOS_VSTART_partition_fw >> 3)
31
32 #else
33 # if (CONFIG_SOC_INTEL_CSE_FW_PARTITION_CMOS_OFFSET != 0)
34 # define PARTITION_FW_CMOS_OFFSET CONFIG_SOC_INTEL_CSE_FW_PARTITION_CMOS_OFFSET
35 # else
36 # error "Must configure CONFIG_SOC_INTEL_CSE_FW_PARTITION_CMOS_OFFSET"
37 # endif
38 #endif
39
40 #define PSR_BACKUP_STATUS_SIGNATURE 0x42525350 /* 'PSRB' */
41
42 /* Helper function to read CSE fpt information from cmos memory. */
cmos_read_fw_partition_info(struct cse_specific_info * info)43 void cmos_read_fw_partition_info(struct cse_specific_info *info)
44 {
45 for (uint8_t *p = (uint8_t *)info, i = 0; i < sizeof(*info); i++, p++)
46 *p = cmos_read(PARTITION_FW_CMOS_OFFSET + i);
47 }
48
49 /* Helper function to write CSE fpt information to cmos memory. */
cmos_write_fw_partition_info(const struct cse_specific_info * info)50 void cmos_write_fw_partition_info(const struct cse_specific_info *info)
51 {
52 for (uint8_t *p = (uint8_t *)info, i = 0; i < sizeof(*info); i++, p++)
53 cmos_write(*p, PARTITION_FW_CMOS_OFFSET + i);
54 }
55
56 /* Read and validate `psr_backup_status` structure from CMOS */
psr_backup_status_cmos_read(struct psr_backup_status * psr)57 static int psr_backup_status_cmos_read(struct psr_backup_status *psr)
58 {
59 for (uint8_t *p = (uint8_t *)psr, i = 0; i < sizeof(*psr); i++, p++)
60 *p = cmos_read(PARTITION_FW_CMOS_OFFSET + sizeof(struct cse_specific_info) + i);
61
62 /* Verify signature */
63 if (psr->signature != PSR_BACKUP_STATUS_SIGNATURE) {
64 printk(BIOS_ERR, "PSR backup status invalid signature\n");
65 return -1;
66 }
67
68 /* Verify checksum over signature and backup_status only */
69 uint16_t csum = ipchksum(psr, offsetof(struct psr_backup_status, checksum));
70
71 if (csum != psr->checksum) {
72 printk(BIOS_ERR, "PSR backup status checksum mismatch\n");
73 return -1;
74 }
75
76 return 0;
77 }
78
79 /* Write `psr_backup_status structure` to CMOS */
psr_backup_status_cmos_write(struct psr_backup_status * psr)80 static void psr_backup_status_cmos_write(struct psr_backup_status *psr)
81 {
82 /* Checksum over signature and backup_status only */
83 psr->checksum = ipchksum(psr, offsetof(struct psr_backup_status, checksum));
84
85 for (uint8_t *p = (uint8_t *)psr, i = 0; i < sizeof(*psr); i++, p++)
86 cmos_write(*p, PARTITION_FW_CMOS_OFFSET + sizeof(struct cse_specific_info) + i);
87 }
88
89 /* Helper function to update the `psr_backup_status` in CMOS memory */
update_psr_backup_status(int8_t status)90 void update_psr_backup_status(int8_t status)
91 {
92 struct psr_backup_status psr;
93
94 /* Read and update psr_backup_status */
95 if (psr_backup_status_cmos_read(&psr) < 0)
96 /* Structure invalid, re-initialize */
97 psr.signature = PSR_BACKUP_STATUS_SIGNATURE;
98
99 psr.value = status;
100
101 /* Write the new status to CMOS */
102 psr_backup_status_cmos_write(&psr);
103
104 printk(BIOS_INFO, "PSR backup status updated\n");
105 }
106
107 /*
108 * Helper function to retrieve the current `psr_backup_status` in CMOS memory
109 * Returns current status on success, the status can be PSR_BACKUP_DONE or PSR_BACKUP_PENDING.
110 * Returns -1 in case of signature mismatch or checksum failure.
111 */
get_psr_backup_status(void)112 int8_t get_psr_backup_status(void)
113 {
114 struct psr_backup_status psr;
115
116 if (psr_backup_status_cmos_read(&psr) < 0)
117 return -1;
118
119 return psr.value;
120 }
121